- Aggregation behaviour of perfluorononanoic acid/sodium dodecyl sulfate mixtures

MARÍA FLORENCIA TORRES; RITA H. DE ROSSI; MARIANA ADELA FERNÁNDEZ

SPRINGER HEIDELBERG

Lugar: HEIDELBERG; Año: 2013 vol. 16 p. 903 - 903

he mixed system of an anionic hydrocarbonsurfactant, sodium dodecyl sulfate, and a perfluorinatedsurfactant, perfluorononanoic acid (PFNA), was investigatedby a combination of methods. The critical micellarconcentrations (CMC) were determined over a wide rangeof sample compositions by surface tension, conductivityand UV–visible spectrophotometry using N-(4-nitrophenyl)perfluorononanamide as a molecular probe. Thevalues of CMC obtained by different techniques were ingood agreement. In addition, the aggregation numbers weredetermined in the mixtures with a low content of hydrocarbonsurfactant, by measuring the fluorescence quenchingof pyrene. The hydrodynamic radii of the aggregateswere estimated through the diffusion ordered 19F- and1H-NMR spectroscopy. The values obtained are in agreementwith those expected according to the measuredaggregation numbers. The analysis of the data with differen